<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
  let zhangsan = {
    name: "zhangsan",
    age: 23,
    addr: "shanghai"
  }
  for (let zhangsanKey in zhangsan) {
    console.log(zhangsan[zhangsanKey]);
    document.write("<h3>",zhangsan[zhangsanKey],"</h3>")
  }
</script>
</body>
</html>